Matthew Cox is a year 11 student at Exeter School; he joined the Femtosecond Lasers and Timing Group at the Accelerator Science and Technology Centre, Daresbury Laboratory, as part of a summer work placement with the STFC. In this article he shares some of his experience working within the group and some of the projects they are working on.
Here at the Femtosecond Lasers and Timing (FLT) group department at ASTeC there are a number of fascinating research projects ranging from laser pulse shaping in time and space to reducing the size of high energy particle accelerators to a size so they can fit in your basement. During my work experience at STFC Daresbury Laboratory I had the opportunity to see the work of the FLT group first hand; in this article, I aim to give you a flavour of work currently underway within the FLT group.
The 'LATTE' laser laboratory
In Daresbury Science Park there are many different research laboratories. One lab, in particular, stands out from the rest, with nine astonishingly powerful lasers set up into intricate configurations with a large number of small glistening lenses and delicate mirrors positioned around a large table. The Lasers, Terahertz and Terawatt Experiments (LATTE) laboratory is situated immediately next to the CLARA particle accelerator and is the research hub of the FLT group.
One key area of research underway in the LATTE laboratory focusses on electron bunch manipulation by terahertz-driven electric fields. Shyamal Mondal (STFC Rutherford International Research Fellow) and Andrei Gorodetsky (Cockcroft Institute Postdoctoral Research Associate) are currently developing the means to accelerate electrons to enormous speeds using non-ionising terahertz radiation (300-3000 GHz). Terahertz radiation is of particular interest for future particle accelerators, providing the means to make the technology far smaller than conventional modern accelerators; this allows the technology to be more accessible for university and industrial sector research. Terahertz radiation by itself has many applications, including medical imaging, enhanced security applications and telecommunications, and members of the group continue to study efficient ways to generate and detect it.
The LATTE lab
Femtosecond laser pulses
Many of the laser systems in the LATTE laboratory produce pulses of electromagnetic radiation between 10 and 100 femtoseconds in duration. This is an extraordinary short time scale on which many electronic processes in chemical and biological structures occur. Some of the experiments use multiple laser systems at the same time. In one system a pair of 10 watt green lasers are focussed onto a titanium sapphire crystal. This is used to amplify near-infrared electromagnetic radiation generated from a different laser system ten times a second. Each pulse of amplified laser light contains 1 joule of energy and is no longer than 50 femtoseconds in duration; this corresponds to a power of 20 terawatts! This system is so powerful that the light must be transported in vacuum, to prevent ionisation of the air which can distort the laser pulses.
As well as high energy laser systems, the laboratory is also used to research low energy, high-precision laser systems. James Henderson (Cockcroft Institute Postdoctoral Research Associate) and Calum Tollervey (STFC graduate laser scientist) joined the FLT group in 2016 and have been working on enhancing the synchronisation of laser pulses to a radio-frequency reference source. Their goal is to be able to match each pulse to the next with a precision of one femtosecond. This involves both laser systems and a large number of high-precision electrical components and James is currently using the LATTE laboratory to investigate how these components work together. This is a vital contribution to the CLARA particle accelerator, currently under development at Daresbury Laboratory, enabling many state-of-the-art concepts the facility aims to develop.
James standing next to his work.
Everyone here is exceptionally passionate about their work, pursuing their dreams of advancing the technology and science of both laser systems and particle accelerators. Their enthusiasm is infectious and spreads quickly to any visitor. I enjoyed not only seeing how committed and devoted to their research everyone here is. According to Shyamal, one of the most enjoyable aspects of working with at ASTeC is the “enormous range of expertise" that is available; everyone working here is very willing to help out at a moment's notice and supply you with extra knowledge. The availability of world class apparatus and equipment facilitates many different experiments and enables world-class research; this keeps the UK at the forefront of international scientific development.
Calum working in the lab.
All photos taken by Matthew Cox during his work experience.